1. Field of the Invention
The present invention relates to an occupant protective apparatus and, in particular, to an occupant protective apparatus which is capable of reducing a deceleration to be applied to an occupant when a car collision occurs.
2. Description of the Related Art
Recently, in order to enhance the effect of occupant protection in a car collision, there have been proposed various car body structures in which the deforming mode of the other remaining portions of a car body than a car room portion of the car body in a car collision is set properly to thereby be able not only to reduce the deceleration of the car room portion of the car body but also to prevent the deformation of the other remaining portions of the car body from extending over to the car room portion of the car body (see JP-A-7-101354).
On the other hand, the deceleration of the occupant restricted to a seat by a seat belt can firstly start at the time when a forwardly going inertial force acting on the occupant in the car collision is received by the seat belt. Here, since the spring action of the seat belt cannot be removed, the inertial force causes the occupant to move forward and the deceleration of the occupant reaches its peak value at the time when the extension of the seat belt reaches its limit. It is generally said that the peak value of the occupant deceleration increases as the moving amount of the occupant due to the inertial force increases and, normally, the peak value of the occupant deceleration becomes higher than the average deceleration of the car room portion of the car body. Therefore, in order to reduce an impact to be given against the occupant due to the car collision, the deceleration of the car body must be adjusted in such a manner that a delay in the starting time of the occupant deceleration with respect to the car body deceleration can be minimized.
However, it is substantially impossible to connect the occupant to the car body as an integral unit and, especially, in the case of a compact car in which it is difficult to secure a sufficient stroke in the other remaining portions of the car body than the car room portion thereof, it is difficult to reduce the occupant deceleration further simply using a conventional occupant protecting method in which the deceleration of the car room portion in a car collision is reduced by properly setting the deforming mode of the car body.
The present invention aims at eliminating the drawbacks found in the above-mentioned conventional occupant protective apparatus. Accordingly, it is an object of the invention to provide an occupant protective apparatus which can reduce not only the size of the car body but also the deceleration of the occupant at a further higher dimension.
In attaining the above object, according to the invention, there is provided an occupant protective apparatus, including: at least one seat supported on a car body to be movable along a direction of a force acting on said car body in the case of a car collision, the seat respectively including a seat belt for restricting an occupant seated thereon; a first fluid container, the capacity of which is reduced in conjunction with the deformation of the car body in the car collision; and a first force generating unit applying to the at lest one seat, a force directed to the backward of the car body in response to the pressure occurring by fluid filled in said fluid container when the capacity thereof is reduced.
According to the present occupant protective apparatus, for example, in case where a forward running car collides head on with a structure on the road, the fluid container disposed in the front end portion of the car body is compressed and the fluid filled in the fluid container is thereby charged into the force generating means such as a liquid pressure cylinder. Due to this, backward going acceleration is applied to the seat at the same time with the occurrence of the car head-on collision to thereby generate in the seat higher deceleration than the deceleration of the car body, which makes it possible to enhance the restricting force of the seat belt for restricting the forward movement of the occupant.
Especially, the present occupant protective apparatus may further include second force generating means for applying a forward going force to the seat after the above-mentioned backward going force is applied. That is, in case where a forward going force is applied to the seat with a proper time delay, an increase in a forward going inertial force acting on the occupant in the car collision can be controlled, so that the deceleration of the car body and the deceleration of the seat and occupant can be made equal to each other in the early stage of the car collision.